/*
 * @lc app=leetcode.cn id=131 lang=cpp
 *
 * [131] 分割回文串
 */
class Solution
{
public:
    vector<vector<string>> partition(string s)
    {
        vector<vector<string>> res;
        vector<string> out;
        helper(s, 0, out, res);
        return res;
    }
    void helper(string s, int start, vector<string> &out, vector<vector<string>> &res)
    {
        if (start == s.size())
        {
            res.push_back(out);
            return;
        }
        for (int i = start; i < s.size(); ++i)
        {
            if (!isPalindrome(s, start, i))
                continue;
            out.push_back(s.substr(start, i - start + 1));
            helper(s, i + 1, out, res);
            out.pop_back();
        }
    }
    bool isPalindrome(string s, int start, int end)
    {
        while (start < end)
        {
            if (s[start] != s[end])
                return false;
            ++start;
            --end;
        }
        return true;
    }
};
